Pond Build

Paschendale52

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Its been about two weeks since I updated and it has been a stressful couple weeks! I got the liner in with the help of some friends and then in classic me fashion I got a little ahead of myself. Long story short, I thought I had the liner with plenty of slack everywhere and so affixed the bottom drain and cut a hole for the smaller window. As I started looking at it further after I had used Lexel and screwed in the bottom drains and cut the hole for the window I realized the liner was actually pretty taut in a couple places. What followed was a week of moving the liner, back filling with some dirt, lining the up the window and eventually filling the pond to the bottom of the windows to check. After filling and draining 3 times I finally had it in a place where I was happy.

All of that finished, I was able to get the top mostly on, finish and test the filtration box, and stage the stock tank bog filters for overflow/waterfall.

Below is the liner in with the windows lexel'd in place and the pond filled up to the concrete, just below the windows. The bottom drain on the left is ~6" deep and the drain in the middle is ~3' deep right now. That will be ~2.5' and 5' once its filled all the way. The windows are acrylic and sandwiched between the Z-bar and a bracket panel. There is a thick bead of Lexel on the front and back side of the acrylic as well as the bolts for the brackets. When I have the final brackets on I'll be ready to fill the pond and test for leaks.

Water in to concrete

The teal toppers provide additional rigidity towards bending. Final steps with those are to attach the 2 missing pieces (the diagonal corners) and then trim and tack the excess liner to the underside for a clean look. The dirt on the white lumber is due to rain causing dirt to jump up. I'll clean it and fill in with gravel/crushed rock around the bottom when the build is done.

Topper in low water Topper ear

The filtration consists of those 2 4" bottom drains and the skimmer. The valves on the left side are overflow to set the pond water level and a drain for draining to ground level. The filter box is a rectangle and has the returns on one side and the pump on the other with spaces for the matala pads for prefiltration. The design is heavily inspired by the concrete filter box in @Markw84 's build.

The small box with the red pump has the air pump and the Bell Gossett pump that Mark recommended in his build for pushing the water into the 2 stock tanks and UV for overflow waterfall return. Those still need the be plumbed and have their stone and plants put in.

Filtration up BellGossett Stock tank return

One final note. I couldn't think of a way to use the skimmer box that I built and be confident in the seal for the liner, so I just bought a skimmer off of amazon designed for above-ground pools.

Skimmer back Skimmer front


On to the final steps! Finish the topper, finish the filtration, rocks and such to make the basking and shallow water areas and then fill it up! I may beat my deadline after all. My wife is due with our first kid in 3 weeks, so it could really be any day now. I'm trying to finish up ahead of kiddo arriving, but things may get delayed for a bit. Only time will tell!
 

Paschendale52

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I'm trying to decide what to do about the basking for the pond. My original thought was to stack up rocks above the water line, but that seems like a lot of rock at this point. I'm wanting an area maybe 4' square and ~6 or 8" deep for digging, egg laying, and basking.

I've considered a floating platform made of non-treated lumber and air-filled PVC or XPS or something for flotation.

I've also thought about stacking up CMU to below the water line, running some boards across it for a platform and then making a pocket with more CMU and then lining it with extra liner and adding dirt/sand to that.

My only thought on the drawbacks for the lumber platform resting on CMU is that if the lumber starts to degrade from being underwater I'll have to dig up all the dirt to replace the boards. Maybe using acrylic or something would be better for the underwater platform to build up the dirt on, but I'm not sure.

Anyone have any thoughts or ideas? I think I'm currently leaning towards the last option, since I'll already be making a small retaining area in the shallow section to add a few inches of sand to for digging and burrowing for the muds and potential future softshells.
 

Sarah2020

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Looks good I would make it as simple as possle in the event you need to clean or dismantle. Could you put build two towers with a bridge between both using upvc or acrylic as you said. Stones will be a risk to your lining. I would avoid wood as you suggested. Others may provide ideas during the day. There have been some amazing ponds shared on here.
 

Paschendale52

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Big progress this week! I got the bog filters in, filled with 3/4" and 3/8" pea gravel and some plants installed. it will fill out in time, but I didn't want to go too crazy since the only nutrition the plants have right now is from a tiny amount of mosquito fish and the dirt that was on the gravel and sand. I'm probably less than a week away from being done, so I think they'll be fine until then.

Bog filter

I worked mostly the last 2 days on buying, moving, and installing the CMU block, sand, and flagstone inside the pond for the internal structure for shallow areas. The full image is below. The lower and smaller area underneath the left bog filter will have about 2' of water over the sand. Its 1 CMU block high and then topped with flagstone and filled with sand. Its about 15 sq ft, the two rectangles that make it up are ~ 4' x 3' and 1.5' x 1.5'.

The basking area is 4 CMU blocks high and isn't finished yet. All CMU blocks here are 6" x 8" x 16"

The larger and taller sandy area is 2 CMU blocks high, and topped with flagstone as well. It took about a yard of sand to fill.

For all of the CMU blocks I filled the voids with 3/8" gravel. for the blocks that are more than 1 CMU high (the larger sand area and the basking area) there is a PVC pipe bound into the gravel through the core of each void to hold them all together. They are also stacked with a running seam so that there are fully bound together.

I purchased a bag of type S mortar on a whim to possibly coat at least the basking area, but I havn't done it yet because I was curious if people had opinions on how good an idea it was. How long would it have to set before I could fill the water to the mortar line?

That blue line in the water is from the internal pump that I have installed until I get the water level high enough to use the filter box and the B&G 2 1/2 pump. That pump is currently moving ~1500 GPH (before head loss) and the B&G will move ~6000 GPH after head loss.

Full pond structure

The basking area is a bit tilted, I got it as vertical as I could stacking gravel bagged in pond underlayment to give a level foundation. Because it is all seamed together and the acrylic basking area base will mate with those PVC pieces that go through each running seam, I'm not worried about it. These faces, and maybe just the front facing one, are the areas I'm most interested in mortaring, but I wanted to hear thoughts on that before I proceeded.
One of the 4" bottom drains is in this area and with the basking area blocking the deep end from this area, the water draining through there will be forced over the sand areas.

Basking area partial

This is the larger sand area. Its about 8' long by 4' wide and the water will be ~1.5' deep over this area. Once I have the pond filled I'll likely add some cholla or other drift woods to this area.

Since my deadline is almost here (my wife is 39 weeks pregnant today), if I don't finish before things go on pause I'll leave the basking area unfinished and keep the water level below the skimmer such that I can make a basking area here from stacked flagstone.

Large sand area

The small sand area has the bog filter return right above it so I added a small flagstone cave to keep the water from landing in the sand and spreading it out. This will be less of a problem when the water level is at its final height. The copper returns for the bog filter are copper coated aluminum that I got at Lowes for $20 and formed into these returns. A cheap and easy return once I siliconed them into place through the stock tanks. Also, the water is pretty murky right now due to all the gravel and sand that I through in. It should clear up in a day or two.

There is nearly 3 tons of gravel between the bog filters and the CMU void fills. And about 1.5 tons of sand.

Small sand area
 

Paschendale52

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Copper? Copper can kill fish, snails, plants, etc.
Do you think the copper coating on the over flow is a potential problem? My thought process was the pipes and fittings that the water flows through to fill the pond are all copper and since the pH isn't going to be far from 7 I wouldn't leach much copper off of a couple overflow plates. I got the idea from seeing copper waterfall overflows at the pond dealer and thought it looked good. I'll keep an eye on things with it for sure. Thanks for the heads up.
 

wellington

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Do you think the copper coating on the over flow is a potential problem? My thought process was the pipes and fittings that the water flows through to fill the pond are all copper and since the pH isn't going to be far from 7 I wouldn't leach much copper off of a couple overflow plates. I got the idea from seeing copper waterfall overflows at the pond dealer and thought it looked good. I'll keep an eye on things with it for sure. Thanks for the heads up.
I don't know. Did the pond dealer have fish? Copper solutions are used in some fish desease treatments, but you have to be very careful to not over dose and then do huge water changes after treating. Some fish can't be treated at all with copper and inverts not at all.
@Markw84 probably would know.
 

Paschendale52

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I don't know. Did the pond dealer have fish? Copper solutions are used in some fish desease treatments, but you have to be very careful to not over dose and then do huge water changes after treating. Some fish can't be treated at all with copper and inverts not at all.
@Markw84 probably would know.
They carry lots of koi, but the copper overflow guy was in a box not in use. If it seems like its going to be a problem I can maybe put a clear coat over it or something. I would think the contact time is so low that it wouldn't be too bad, but I'm of course open to any advice.
 

NorCal tortoise guy

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They carry lots of koi, but the copper overflow guy was in a box not in use. If it seems like its going to be a problem I can maybe put a clear coat over it or something. I would think the contact time is so low that it wouldn't be too bad, but I'm of course open to any advice.
With ph at 7 your copper will be fine. Even at an acidic ph that would eat at the copper it shouldn’t really be a problem because there is so little copper.
 

Markw84

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Thanks! Any thoughts on the mortar coat on the CMU blocks? Is that what you did for your waterfall? Except yours was mortared together rather than dry stacked and filled with gravel.
I added additional pure cement and also used latex additive to make it more water proof. In addition to the color added.

A though for your consideration;

I always try to avoid areas like your sand or gravel filled blocks that can accumulate organic material over time and stagnate. This eventually leads to a struggle with water quality and high nitrates as these become areas of trapped matter that do not get filtered out.
 

Paschendale52

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I added additional pure cement and also used latex additive to make it more water proof. In addition to the color added.

A though for your consideration;

I always try to avoid areas like your sand or gravel filled blocks that can accumulate organic material over time and stagnate. This eventually leads to a struggle with water quality and high nitrates as these become areas of trapped matter that do not get filtered out.
Thanks for the advice. Does that apply to the sandy areas that are for the turtles to have an exploration/hang out spot (the big sandy areas) or more for the CMU fill? Right now either one is more than I'll be able to change before I don't have the time to work on it anymore, but its good to have as a point of reference. If I have problems with it when I get back to having availability to work on it (how long are kids a lot of work? :) ) I'll keep that as a point to fix. What would will the CMU blocks with for stability? Mortar or more concrete?

If I'm thinking about having softshells and mud/musk turtles that like to explore the bottoms a lot what would you recommend?
 

Markw84

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If you have softshells, you have to have the sand. That's one of the reasons I do not have softshells (plus they are fish hunters and too good at catching fish I also want in the pond). Mud and musk turtles do very well on bare bottom ponds as long as there are hiding spots. Plants with roots growing into the water are great for this and for filtration.

I'm sharing experience only for reference not to discourage. I have personally abondonded any attempts to build a nesting area inside the pond area. I've come to the point that I only make nesting areas outside the pond itself. So I have access to nesting areas outside the pond's waterproof shell and the filtered water area. I will make basking areas inside the pond area, but it is stacked block and flat stones. No areas to trap unfiltered sediment that could form.
 

Paschendale52

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If you have softshells, you have to have the sand. That's one of the reasons I do not have softshells (plus they are fish hunters and too good at catching fish I also want in the pond). Mud and musk turtles do very well on bare bottom ponds as long as there are hiding spots. Plants with roots growing into the water are great for this and for filtration.

I'm sharing experience only for reference not to discourage. I have personally abondonded any attempts to build a nesting area inside the pond area. I've come to the point that I only make nesting areas outside the pond itself. So I have access to nesting areas outside the pond's waterproof shell and the filtered water area. I will make basking areas inside the pond area, but it is stacked block and flat stones. No areas to trap unfiltered sediment that could form.

Interesting. I don't feel discouraged, just food for thought for the future.

I was thinking the sandy areas are also going to be good places to stick plants and such. I suppose thats more because its flat than the sand itself. The way I built my pond I don't have a lot of flat places to put hiding spots outside of the sandy areas, which is where I had planned on putting them. I'll bridge some large flagstones over dips in the bottom in the deeper area, as well.

Since I already have the sandy areas and won't be getting rid of them for a long time (because I won't have time with the new kid I assume) I could still go for softshells. I don't plan on having prized koi or anything like that so the idea of fish hunting doesn't bother me. They would also be years down the line since I plan on raising anything indoors for a few years before it goes in the pond.

The nesting area is mostly a product of not having a way to have one outside of the pond. I suppose it would be possible to have a bridge that is protected to get out of the water and bridge outside to something, but it would be a really big build that would be a couple years away for the same reason. Do you think thats something worth doing? If I did that I could get rid of the nesting area inside the pond. My razorback musk turtle laid an infertile egg on a piece of floating cork back before we moved from CA and so I'm thinking they would need something like that. I would like to do something like your backyard where there is an out of pond area around the pond itself, but that isn't really feasible at this house. If I don't have a nesting/laying area, will it be stressful for the turtles to lay without somewhere to do it?
 

Paschendale52

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As far as the basking area. This is complete except for filling in with dirt/sand. My plan was a 50/50 mix. The acrylic bridges the 2 CMU walls with a single 3/4" PVC all the way through the arcylic, lower walls, and topside CMU ring in each void of the CMU (6 voids per side, 12 PVC reinforcement pieces). The topside CMU ring is also filled with gravel just for weight and is lexel'd to the acrylic. It has a layer of underlayment, then a pond liner, then another underlayment in the middle which will keep in waterproof. The nominal water level is about halfway up the CMU wall and I'll have something for a ramp.

After our discussion above, I'm curious if I should stick with this plan because I have so much gravel/deadspace already it doesn't matter, or if it would be better to go ahead and remove the gravel-filled CMU and just stack flagstone directly on the acrylic until its above the water level. That would make it strictly a basking area, not a basking/nesting area.

When/if I fill in with sand/dirt I'll also trim back a lot of the exposed liner/underlyament.

Thoughts? Basking area near finished Basking area view 2
 

Paschendale52

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Another thought: If the sand-filled areas are a problem because nothing can penetrate them, perhaps an alternative (still in the future of course) to replacing them would be to put a network of 1/2" or 3/4" PVC at the bottom of them and flow air up through them once a month or so. That would prevent oxygenation deprivation and stagnation and such. Any thoughts there?

I'd probably have to get a solids pump to temporarily remove all of the sand, but I don't see why that couldn't be done.
 

Paschendale52

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Final build update!

The finished build is below. I'll continue to update in this thread as time progresses for the build-related stuff, but I'll make a new thread for stocking etc.

There isn't much to the build since the last update except that I replaced the basking platform with a small concrete mixing trough with dirt/sand and mostly flag stone. The pond is filled to final depth here. I measured the diameter of the pond at its widest every day for a week after filling. I wanted to see that the raised area was nice and sturdy. The diameter didn't change at all until I was about 4" down from the nominal water level. I left it here for about 3 days to make sure and then filled the last 4". After final depth filling the diameter increased by about 0.5" across the 10' wide span and 30" height, which is about 0.5 degrees total or 0,25 degrees per side. I'm pretty happy with this and will continue to measure once a week or so. I expect wood to have some flex to it that CMU blocks wouldn't.

Complete day 14


After about 1.5 weeks (and one baby), I added 10 small koi and 10 small comet goldfish just to get things going and have some life in the pond beyond the mosquito fish. I tried to take photos of them, but the reflections off the water kept them from being seen. They have been staying pretty deep and I havn't seen them eat yet, but its been less than a day since I added them. I figure I'll add the turtles from the indoor 180 gallon aquarium in another week or so.

In addition to the bog filter plants I also grabbed a water lily. Its put on about 3 pads and a flower since I got it a week ago. I'm hoping that with 2 weeks before the relatively small turtles get added, it will be able to stick around, if not I'll just consider it a turtle snack and try again next spring.
Lily

Here is the replaced basking area. You can see I left the PVC that was through the top CMU to make sure things stay together. I also like it as boundary to keep the turtles from going near the edge of the pond or diving off the other direction.

Basking area finished

The bog filter is growing in nice and thick and I added a couple iris and bulrush to help out and be something tall and visible. I'm hoping that I can add some bulrush to the sandy area in the main pond as well to give more cover with something the turtles won't eat.

Bog1

So thats it! As I said, I'm hoping to move some turtles over in a week or so.

I'm still undecided on the species of hatchling to add to my indoor aquarium after I move its current residents outside and would love any suggestions. I'm leaning towards Mexican giant musk turtle (staurotypus triporcatus), but am open to other ideas and suggestions for breeders of this or another suggested species.

Thanks for keeping up with the build and the suggestions along the way!
 

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